Company / CIK 0001057352
COSTAR GROUP, INC.
- Ticker
- CSGP
- Size, estimated from filings
- Large cap ($10B – $200B)
- Insiders on file
- 16
- Members of Congress who traded it
- 2
- Federal contracts on record
- none matched
- Lobbying filings on record
- 10
- SEC filings
- EDGAR ↗
- Latest trade on record
- October 15, 2026
COSTAR GROUP, INC. (CSGP) has 16 insiders on file who disclosed 63 transactions in the last 12 months (7 open-market buys, 34 sales, about $18.0M at reported prices), and 9 congressional trades in its stock are on record. No federal contract award that started in the last 180 days was found for a recipient with exactly this name, and 6 lobbying filings naming it as client report $330K in 2026.
COSTAR GROUP, INC. in charts
Who is trading this stock
Which people account for the buying and selling over the last 12 months?
BoughtSold
8 people account for the disclosed buying and selling in COSTAR GROUP, INC. over the last 12 months; the most active is FLORANCE ANDREW C with $12M.
Lobbying spend by quarter
How much has COSTAR GROUP, INC. reported spending on federal lobbying?
COSTAR GROUP, INC. reported $570K in lobbying over the last eight quarters, from filings matched by exact company name.
Insiders
| Name | Role | Rows | Bought | Sold | Last filed |
|---|---|---|---|---|---|
| Rossmann Robin Jack | Chief Financial Officer | 2 | 0 | 1 | October 16, 2026 |
| McCarthy Christine M | Director | 1 | 0 | 0 | October 14, 2026 |
| LOWN CHRISTIAN M. | Chief Financial Officer | 4 | 0 | 2 | September 8, 2026 |
| Cann Cynthia Cammett | Chief Accounting Officer | 9 | 0 | 6 | August 10, 2026 |
| Hill John W | Director | 3 | 0 | 2 | August 10, 2026 |
| FLORANCE ANDREW C | President and CEO | 10 | 4 | 4 | August 5, 2026 |
| SAINT FREDERICK G. | President, Marketplaces | 7 | 1 | 5 | August 4, 2026 |
| Glaser Rachel C | Director | 2 | 1 | 0 | June 24, 2026 |
| Sams Louise S | Director | 2 | 1 | 0 | June 24, 2026 |
| Musslewhite Robert W | Director | 1 | 0 | 0 | June 24, 2026 |
| Brunner Angelique G. | Director | 1 | 0 | 0 | June 24, 2026 |
| BERISFORD JOHN L | Director | 1 | 0 | 0 | June 24, 2026 |
| Ruggles Lisa | Senior VP, Global Operations | 6 | 0 | 5 | March 17, 2026 |
| SIMURO FRANK | Chief Technology Officer | 6 | 0 | 5 | March 17, 2026 |
| DESMARAIS MICHAEL J | Chief Human Resources Officer | 4 | 0 | 2 | March 17, 2026 |
| Boxer Gene | General Counsel and Secretary | 4 | 0 | 2 | March 17, 2026 |
Rows are this company's Form 4 rows for each person. "Bought" and "sold" count open-market purchases (code P) and sales only. More in insider buying and insider selling.
Members of Congress who traded CSGP
From periodic transaction reports that name the company's stock. Amounts are the sums of the ranges as filed. Every row is on the CSGP page.
| Member | Seat | Trades | Bought | Sold | Range as filed | Latest |
|---|---|---|---|---|---|---|
| Gilbert Ray Cisneros, Jr. | Representative (CA, District 31), Democrat | 8 | 7 | 1 | $8,008–$120K | August 19, 2026 |
| Lisa C. McClain | Representative (MI, District 9), Republican | 1 | 0 | 1 | $1,001–$15K | September 25, 2025 |
Insider transactions
| Filer | Security | Side | Trade date | Disclosed | Lag | Shares | Price | Value | Flags | Source | Share |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Rossmann Robin Jack | CSGP | Sell F | October 15, 2026 | October 16, 2026 | 1d | 756 | $32 | $24K | Form 4 ↗ | ||
| Cann Cynthia Cammett | CSGP | Sell S | August 7, 2026 | August 10, 2026 | 3d | 4,788 | $31 | $147K | Form 4 ↗ | ||
| Hill John W | CSGP | Sell S | August 5, 2026 | August 10, 2026 | 5d | 3,500 | $30 | $106K | late | Form 4 ↗ | |
| FLORANCE ANDREW C | CSGP | Buy P | August 4, 2026 | August 5, 2026 | 1d | 83,300 | $30 | $2.5M | Form 4 ↗ | ||
| Rossmann Robin Jack | CSGP | Other A | July 31, 2026 | August 4, 2026 | 4d | 34,771 | — | — | derivative | Form 4 ↗ | |
| Cann Cynthia Cammett | CSGP | Other A | July 31, 2026 | August 4, 2026 | 4d | 26,078 | — | — | derivative | Form 4 ↗ | |
| Cann Cynthia Cammett | CSGP | Sell F | August 1, 2026 | August 4, 2026 | 3d | 1,077 | $29 | $31K | Form 4 ↗ | ||
| SAINT FREDERICK G. | CSGP | Sell F | August 1, 2026 | August 4, 2026 | 3d | 1,436 | $29 | $41K | Form 4 ↗ | ||
| LOWN CHRISTIAN M. | CSGP | Sell F | July 1, 2026 | July 6, 2026 | 5d | 5,597 | $29 | $164K | late | Form 4 ↗ | |
| Glaser Rachel C | CSGP | Other A | June 23, 2026 | June 24, 2026 | 1d | 8,262 | — | — | Form 4 ↗ | ||
| BERISFORD JOHN L | CSGP | Other A | June 23, 2026 | June 24, 2026 | 1d | 8,262 | — | — | Form 4 ↗ | ||
| Hill John W | CSGP | Other A | June 23, 2026 | June 24, 2026 | 1d | 8,262 | — | — | Form 4 ↗ | ||
| Brunner Angelique G. | CSGP | Other A | June 23, 2026 | June 24, 2026 | 1d | 8,262 | — | — | Form 4 ↗ | ||
| Musslewhite Robert W | CSGP | Other A | June 23, 2026 | June 24, 2026 | 1d | 8,262 | — | — | Form 4 ↗ | ||
| Sams Louise S | CSGP | Other A | June 23, 2026 | June 24, 2026 | 1d | 8,262 | — | — | Form 4 ↗ | ||
| McCarthy Christine M | CSGP | Other A | June 23, 2026 | June 24, 2026 | 1d | 8,262 | — | — | Form 4 ↗ | ||
| Cann Cynthia Cammett | CSGP | Sell F | June 15, 2026 | June 16, 2026 | 1d | 461 | $32 | $15K | Form 4 ↗ | ||
| FLORANCE ANDREW C | CSGP | Buy P | May 1, 2026 | May 4, 2026 | 3d | 3,100 | $36 | $111K | Form 4 ↗ | ||
| FLORANCE ANDREW C | CSGP | Buy P | May 1, 2026 | May 4, 2026 | 3d | 68,330 | $35 | $2.4M | Form 4 ↗ | ||
| Ruggles Lisa | CSGP | Sell F | March 15, 2026 | March 17, 2026 | 2d | 2,977 | $44 | $130K | Form 4 ↗ | ||
| Boxer Gene | CSGP | Sell F | March 15, 2026 | March 17, 2026 | 2d | 428 | $44 | $19K | Form 4 ↗ | ||
| SIMURO FRANK | CSGP | Sell F | March 15, 2026 | March 17, 2026 | 2d | 11,107 | $44 | $485K | Form 4 ↗ | ||
| DESMARAIS MICHAEL J | CSGP | Sell F | March 15, 2026 | March 17, 2026 | 2d | 2,873 | $44 | $125K | Form 4 ↗ | ||
| Cann Cynthia Cammett | CSGP | Sell F | March 15, 2026 | March 17, 2026 | 2d | 1,194 | $44 | $52K | Form 4 ↗ | ||
| Cann Cynthia Cammett | CSGP | Other A | March 10, 2026 | March 11, 2026 | 1d | 4,374 | — | — | Form 4 ↗ | ||
| FLORANCE ANDREW C | CSGP | Other A | March 10, 2026 | March 11, 2026 | 1d | 124,162 | — | — | Form 4 ↗ | ||
| LOWN CHRISTIAN M. | CSGP | Other A | March 10, 2026 | March 11, 2026 | 1d | 12,268 | — | — | Form 4 ↗ | ||
| Boxer Gene | CSGP | Other A | March 10, 2026 | March 11, 2026 | 1d | 21,920 | — | — | Form 4 ↗ | ||
| DESMARAIS MICHAEL J | CSGP | Other A | March 10, 2026 | March 11, 2026 | 1d | 17,676 | — | — | Form 4 ↗ | ||
| Sams Louise S | CSGP | Buy P | March 6, 2026 | March 9, 2026 | 3d | 1,000 | $48 | $48K | Form 4 ↗ | ||
| LOWN CHRISTIAN M. | CSGP | Other A | February 27, 2026 | March 3, 2026 | 4d | 39,652 | — | — | derivative | Form 4 ↗ | |
| LOWN CHRISTIAN M. | CSGP | Sell F | March 1, 2026 | March 3, 2026 | 2d | 7,175 | $45 | $320K | Form 4 ↗ | ||
| SAINT FREDERICK G. | CSGP | Other A | February 27, 2026 | March 3, 2026 | 4d | 39,652 | — | — | derivative | Form 4 ↗ | |
| FLORANCE ANDREW C | CSGP | Other A | February 27, 2026 | March 3, 2026 | 4d | 83,708 | — | — | derivative | Form 4 ↗ | |
| FLORANCE ANDREW C | CSGP | Sell F | March 1, 2026 | March 3, 2026 | 2d | 59,593 | $45 | $2.7M | Form 4 ↗ | ||
| Boxer Gene | CSGP | Other A | February 27, 2026 | March 3, 2026 | 4d | 26,888 | — | — | derivative | Form 4 ↗ | |
| Boxer Gene | CSGP | Sell F | March 1, 2026 | March 3, 2026 | 2d | 4,547 | $45 | $203K | Form 4 ↗ | ||
| DESMARAIS MICHAEL J | CSGP | Other A | February 27, 2026 | March 3, 2026 | 4d | 17,926 | — | — | derivative | Form 4 ↗ | |
| DESMARAIS MICHAEL J | CSGP | Sell F | March 1, 2026 | March 3, 2026 | 2d | 6,353 | $45 | $284K | Form 4 ↗ | ||
| Cann Cynthia Cammett | CSGP | Other A | February 27, 2026 | March 3, 2026 | 4d | 6,834 | — | — | derivative | Form 4 ↗ | |
| Cann Cynthia Cammett | CSGP | Sell F | March 1, 2026 | March 3, 2026 | 2d | 1,385 | $45 | $62K | Form 4 ↗ | ||
| Ruggles Lisa | CSGP | Other A | February 27, 2026 | March 3, 2026 | 4d | 28,197 | — | — | derivative | Form 4 ↗ | |
| Ruggles Lisa | CSGP | Sell F | March 1, 2026 | March 3, 2026 | 2d | 8,931 | $45 | $399K | Form 4 ↗ | ||
| SIMURO FRANK | CSGP | Other A | February 27, 2026 | March 3, 2026 | 4d | 52,869 | — | — | derivative | Form 4 ↗ | |
| SIMURO FRANK | CSGP | Sell F | March 1, 2026 | March 3, 2026 | 2d | 18,702 | $45 | $835K | Form 4 ↗ | ||
| Glaser Rachel C | CSGP | Buy P | March 2, 2026 | March 3, 2026 | 1d | 1,000 | $45 | $45K | Form 4 ↗ | ||
| SAINT FREDERICK G. | CSGP | Buy P | March 2, 2026 | March 3, 2026 | 1d | 20,000 | $45 | $907K | Form 4 ↗ | ||
| SAINT FREDERICK G. | CSGP | Sell F | March 1, 2026 | March 3, 2026 | 2d | 11,096 | $45 | $495K | Form 4 ↗ | ||
| FLORANCE ANDREW C | CSGP | Buy P | February 27, 2026 | March 2, 2026 | 3d | 55,720 | $45 | $2.5M | Form 4 ↗ | ||
| SIMURO FRANK | CSGP | Sell F | February 19, 2026 | February 23, 2026 | 4d | 4,421 | $49 | $217K | Form 4 ↗ | ||
| SIMURO FRANK | CSGP | Sell D | February 19, 2026 | February 23, 2026 | 4d | 30,727 | — | — | Form 4 ↗ | ||
| SAINT FREDERICK G. | CSGP | Sell F | February 19, 2026 | February 23, 2026 | 4d | 2,149 | $49 | $105K | Form 4 ↗ | ||
| SAINT FREDERICK G. | CSGP | Sell D | February 19, 2026 | February 23, 2026 | 4d | 17,583 | — | — | Form 4 ↗ | ||
| FLORANCE ANDREW C | CSGP | Sell F | February 19, 2026 | February 23, 2026 | 4d | 19,221 | $49 | $943K | Form 4 ↗ | ||
| FLORANCE ANDREW C | CSGP | Sell D | February 19, 2026 | February 23, 2026 | 4d | 104,983 | — | — | Form 4 ↗ | ||
| Ruggles Lisa | CSGP | Sell F | February 19, 2026 | February 23, 2026 | 4d | 3,219 | $49 | $158K | Form 4 ↗ | ||
| Ruggles Lisa | CSGP | Sell D | February 19, 2026 | February 23, 2026 | 4d | 17,583 | — | — | Form 4 ↗ | ||
| SIMURO FRANK | CSGP | Sell F | February 15, 2026 | February 18, 2026 | 3d | 4,151 | $45 | $187K | Form 4 ↗ | ||
| FLORANCE ANDREW C | CSGP | Sell F | February 15, 2026 | February 18, 2026 | 3d | 17,482 | $45 | $787K | Form 4 ↗ | ||
| Ruggles Lisa | CSGP | Sell F | February 15, 2026 | February 18, 2026 | 3d | 3,576 | $45 | $161K | Form 4 ↗ | ||
| SAINT FREDERICK G. | CSGP | Sell F | February 15, 2026 | February 18, 2026 | 3d | 2,424 | $45 | $109K | Form 4 ↗ | ||
| Hill John W | CSGP | Sell S | November 13, 2025 | November 17, 2025 | 4d | 2,250 | $69 | $155K | Form 4 ↗ | ||
| Cann Cynthia Cammett | CSGP | Sell S | November 13, 2025 | November 17, 2025 | 4d | 1,841 | $69 | $127K | Form 4 ↗ |
Federal contracts (USAspending, awards started in the last 180 days)
No contract award starting in the last 180 days was found for a recipient named exactly "COSTAR GROUP, INC.". Subsidiaries and differently-spelled recipients are not matched — search contracts.
Lobbying (Senate LDA, as client)
| Period | Registrant | Primary issue | Amount | Source |
|---|---|---|---|---|
| 2026 Q2 | MILLER STRATEGIES, LLC | Housing | $90,000 | LDA ↗ |
| 2026 Q2 | PENN AVENUE PARTNERS | Real Estate/Land Use/Conservation | $60,000 | LDA ↗ |
| 2026 Q2 | POLARIS GOVERNMENT RELATIONS, LLC | Real Estate/Land Use/Conservation | $60,000 | LDA ↗ |
| 2026 Q2 | MILLER STRATEGIES, LLC | Housing | — | LDA ↗ |
| 2026 Q1 | PENN AVENUE PARTNERS | Real Estate/Land Use/Conservation | $60,000 | LDA ↗ |
| 2026 Q1 | POLARIS GOVERNMENT RELATIONS, LLC | Real Estate/Land Use/Conservation | $60,000 | LDA ↗ |
| 2025 Q4 | POLARIS GOVERNMENT RELATIONS, LLC | Real Estate/Land Use/Conservation | $60,000 | LDA ↗ |
| 2025 Q4 | PENN AVENUE PARTNERS | Real Estate/Land Use/Conservation | $60,000 | LDA ↗ |
| 2025 Q3 | POLARIS GOVERNMENT RELATIONS, LLC | Real Estate/Land Use/Conservation | $60,000 | LDA ↗ |
| 2025 Q3 | PENN AVENUE PARTNERS | Real Estate/Land Use/Conservation | $60,000 | LDA ↗ |
Related companies
Companies whose stock was traded by the same people who traded CSGP, by number of filers in common. It shows overlap in public filings and nothing else.
- Uber Technologies, Inc UBER 2 filers in common
- Datadog, Inc. DDOG 2 filers in common
- Arista Networks, Inc. ANET 2 filers in common
- Meta Platforms, Inc. META 2 filers in common
- NETFLIX INC NFLX 2 filers in common
- INTUIT INC. INTU 2 filers in common
- APPFOLIO INC APPF 2 filers in common
- NVIDIA CORP NVDA 2 filers in common
Guides for this page
- What is SEC Form 4? Who files: officers, directors and owners of more than 10% of a class of the company's shares.
- Insider buying vs insider selling Selling outweighs buying by a wide margin in normal times.
- Lobbying disclosure reports Reports are due about 20 days after each quarter ends.
- What disclosure data cannot tell you Filings are late by design: up to 45 days for Congress, two business days for insiders.
Sources and method
| Source | Filings | Rows | First filed | Newest filed | Read the originals |
|---|---|---|---|---|---|
| House Clerk, periodic transaction reports | 8 | 9 | October 10, 2025 | September 10, 2026 | House Clerk search |
| SEC EDGAR, Form 4 | 49 | 63 | November 17, 2025 | October 16, 2026 | Form 4 list on EDGAR |
| Lobbying disclosure filings | 10 filings | — | — | — | LDA.gov search |
Site built October 22, 2026. Every row in the tables above links to its own filing. To quote a figure, use the Cite button at the top of the page; see how to cite and reuse.
Insiders and their transactions come from SEC EDGAR Form 4 filings for this issuer. Contracts and lobbying are matched by exact normalized name (suffixes like Inc./Corp. ignored) to USAspending recipients and LDA clients — a conservative match that misses subsidiaries on purpose. See methodology and corrections.
Not investment advice. Public records shown as filed; no recommendation is made or implied.